Known image forming apparatuses form an image by developing an electrostatic latent image formed on a photosensitive member with toner. For example, in the image forming apparatus disclosed in JP-A-2003-271030, sheets are fed one-by-one by a pick-up roller to a sheet feed path from a sheet accommodating portion disposed on a lower part of the image forming apparatus. An image is formed on the sheet while the sheet is being fed along the sheet feed path. After image formation, the sheet is discharged onto a discharge tray provided on an upper part of the image forming apparatus.
The image forming apparatus includes a process unit having a photosensitive member and a toner tank, a scanner unit having a polygon mirror for forming an electrostatic latent image on the photosensitive member with a scanning laser beam, and a fixing unit for thermally fixing a visible toner image transferred from the photosensitive member to a sheet.
In the vicinity of the pick-up roller, the sheet accommodating portion, the pick-up roller, the process unit, and the scanner unit are disposed in a stacked manner in a direction corresponding to the height of the image forming apparatus.
In the vicinity of the fixing unit, the sheet accommodating portion, the fixing unit, and the discharge tray are disposed in a stacked manner in the direction corresponding to the height of the image forming apparatus.
In the image forming apparatus, the process unit is moved in a substantially horizontal direction when removed from the image forming apparatus, passing through a space between the pick-up roller and the scanner unit. Such removal might occur, for example, when an amount of toner remaining in the toner tank becomes small, so that the process unit can be replaced.
Because the sheet accommodating portion, the pick-up roller, the process unit, and the scanner unit are disposed in a stacked manner, the image forming apparatus must have a height greater than the stacked height of the sheet accommodating portion, the pick-up roller, the process unit, and the scanner unit. Consequently, this limitation on the minimum height of the image forming apparatus prevents reductions in the overall size of the image forming apparatus.
Likewise, the stacked arrangement of the sheet accommodating portion, the fixing unit, and the discharge tray places an undesirable limitation on the minimum height of the image forming apparatus.
Significant changes in the arrangement of the above-described components in the image forming apparatus to reduce the overall height of the image forming apparatus can necessitate the inclusion of additional components and may cause removal of the process unit to be difficult.